In information-based economies, sensitive and/or valuable information may be available through transactions relying on systematically assigned identifiers. The identifiers can identify financial accounts, persons, personal property (e.g., a VIN number used to uniquely identify an automobile), transaction records (e.g., medical records), and many other sources of information.
One example of such an identifier is a Social Security Number (SSN), issued to citizens, permanent residents, or temporary residents of the United States by the Social Security Administration. Originally created as an identifier for an account tracking an individual's earnings, the SSN is now frequently used as an identifier to verify the identity of an individual. Identity verification using an SSN may be required, for example, when applying for credit, opening a bank account, verifying immigration status, seeking health care, and many other transactions critical to participation in a modern economy. As such, the SSN is commonly sought by identity thieves or falsified as part of fraudulent activities.